[PATCH v5 01/11] kselftest: arm64: add skeleton Makefile

[Cristian Marussi <cristian.marussi@arm.com>]

Add a new arm64-specific empty subsystem amongst TARGETS of KSFT build
framework; keep these new arm64 KSFT testcases separated into distinct
subdirs inside tools/testing/selftests/arm64/ depending on the specific
subsystem targeted.

Add into toplevel arm64 KSFT Makefile a mechanism to guess the effective
location of Kernel headers as installed by KSFT framework.

Merge with

commit 9ce1263033cd ("selftests, arm64: add a selftest for passing
		     tagged pointers to kernel")

while moving such KSFT tags tests inside their own subdirectory
(arm64/tags).

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v4 --> v5
- rebased on arm64/for-next/core
- merged this patch with KSFT arm64 tags patch, while moving the latter
  into its own subdir
- moved kernel header includes search mechanism from KSFT arm64
  SIGNAL Makefile
- export proper top_srcdir ENV for lib.mk
v3 --> v4
- comment reword
- simplified documentation in README
- dropped README about standalone
---
 tools/testing/selftests/Makefile              |  1 +
 tools/testing/selftests/arm64/Makefile        | 70 +++++++++++++++++--
 tools/testing/selftests/arm64/README          | 20 ++++++
 tools/testing/selftests/arm64/tags/Makefile   | 10 +++
 .../arm64/{ => tags}/run_tags_test.sh         |  0
 .../selftests/arm64/{ => tags}/tags_test.c    |  0
 6 files changed, 95 insertions(+), 6 deletions(-)
 create mode 100644 tools/testing/selftests/arm64/README
 create mode 100644 tools/testing/selftests/arm64/tags/Makefile
 rename tools/testing/selftests/arm64/{ => tags}/run_tags_test.sh (100%)
 rename tools/testing/selftests/arm64/{ => tags}/tags_test.c (100%)

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 25b43a8c2b15..1722dae9381a 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 TARGETS = android
+TARGETS += arm64
 TARGETS += bpf
 TARGETS += breakpoints
 TARGETS += capabilities
diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
index a61b2e743e99..5dbb0ffdfc9a 100644
--- a/tools/testing/selftests/arm64/Makefile
+++ b/tools/testing/selftests/arm64/Makefile
@@ -1,11 +1,69 @@
 # SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 ARM Limited
 
-# ARCH can be overridden by the user for cross compiling
-ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+# When ARCH not overridden for crosscompiling, lookup machine
+ARCH ?= $(shell uname -m)
+ARCH := $(shell echo $(ARCH) | sed -e s/aarch64/arm64/)
 
-ifneq (,$(filter $(ARCH),aarch64 arm64))
-TEST_GEN_PROGS := tags_test
-TEST_PROGS := run_tags_test.sh
+ifeq ("x$(ARCH)", "xarm64")
+SUBDIRS := tags
+else
+SUBDIRS :=
 endif
 
-include ../lib.mk
+CFLAGS := -Wall -O2 -g
+
+# A proper top_srcdir is needed by KSFT(lib.mk)
+top_srcdir = ../../../../..
+
+# Additional include paths needed by kselftest.h and local headers
+CFLAGS += -I$(top_srcdir)/tools/testing/selftests/
+
+# Guessing where the Kernel headers could have been installed
+# depending on ENV config
+ifeq ($(KBUILD_OUTPUT),)
+khdr_dir = $(top_srcdir)/usr/include
+else
+# the KSFT preferred location when KBUILD_OUTPUT is set
+khdr_dir = $(KBUILD_OUTPUT)/kselftest/usr/include
+endif
+
+CFLAGS += -I$(khdr_dir)
+
+export CC
+export CFLAGS
+export top_srcdir
+
+all:
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		mkdir -p $$BUILD_TARGET;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+install: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+run_tests: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+# Avoid any output on non arm64 on emit_tests
+emit_tests: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+clean:
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+.PHONY: all clean install run_tests emit_tests
diff --git a/tools/testing/selftests/arm64/README b/tools/testing/selftests/arm64/README
new file mode 100644
index 000000000000..aca892e62a6c
--- /dev/null
+++ b/tools/testing/selftests/arm64/README
@@ -0,0 +1,20 @@
+KSelfTest ARM64
+===============
+
+- These tests are arm64 specific and so not built or run but just skipped
+  completely when env-variable ARCH is found to be different than 'arm64'
+  and `uname -m` reports other than 'aarch64'.
+
+- Holding true the above, ARM64 KSFT tests can be run within the KSelfTest
+  framework using standard Linux top-level-makefile targets:
+
+      $ make TARGETS=arm64 kselftest-clean
+      $ make TARGETS=arm64 kselftest
+
+      or
+
+      $ make -C tools/testing/selftests TARGETS=arm64 \
+		INSTALL_PATH=<your-installation-path> install
+
+   Further details on building and running KFST can be found in:
+     Documentation/dev-tools/kselftest.rst
diff --git a/tools/testing/selftests/arm64/tags/Makefile b/tools/testing/selftests/arm64/tags/Makefile
new file mode 100644
index 000000000000..76205533135b
--- /dev/null
+++ b/tools/testing/selftests/arm64/tags/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+# ARCH can be overridden by the user for cross compiling
+ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+
+ifneq (,$(filter $(ARCH),aarch64 arm64))
+TEST_GEN_PROGS := tags_test
+TEST_PROGS := run_tags_test.sh
+endif
+
+include ../../lib.mk
diff --git a/tools/testing/selftests/arm64/run_tags_test.sh b/tools/testing/selftests/arm64/tags/run_tags_test.sh
similarity index 100%
rename from tools/testing/selftests/arm64/run_tags_test.sh
rename to tools/testing/selftests/arm64/tags/run_tags_test.sh
diff --git a/tools/testing/selftests/arm64/tags_test.c b/tools/testing/selftests/arm64/tags/tags_test.c
similarity index 100%
rename from tools/testing/selftests/arm64/tags_test.c
rename to tools/testing/selftests/arm64/tags/tags_test.c
-- 
2.17.1